Processing of flexible substrates, such as plastic films or foils, is in high demand in the packaging industry, semiconductor industries and other industries. Processing may include coating of a flexible substrate with a desired material, such as a metal, semiconductors and dielectric materials, etching and other processing steps conducted on a substrate for the desired applications. Systems performing this task generally include a processing drum, e.g., a cylindrical roller, coupled to a processing system for transporting the substrate, and on which at least a portion of the substrate is processed. Roll-to-roll coating systems can, thereby, provide a high throughput system.
Typically, a coating process, such as a chemical evaporation process or a thermal evaporation process, can be utilized for depositing thin layers of materials onto flexible substrates. However, Roll-to-Roll deposition systems are also experiencing a strong increase in demand in the display industry and the photovoltaic (PV) industry. For example, touch panel elements, flexible displays, and flexible PV modules result in an increasing demand of depositing suitable layers in Roll-to-Roll coaters, particularly with low manufacturing costs. However, such devices typically have several layers, which are typically manufactured with CVD processes and particularly also PECVD processes.
Deposition apparatuses with e.g. CVD, PECVD and/or PVD sources, wherein different residues from gas mixtures are deposited in the same processing region in subsequent uses of the equipment have the need of in depth cleaning procedures in order to avoid cross contamination effects and to ensure the long term process stability. Commonly, for this purpose, processing chambers are opened and cleaned manually, which may result in increased machine downtime.
Over the years, layers in display devices have evolved into multiple layers with each layer serving a different function. Depositing multiple layers onto multiple substrates may require multiple processing chambers, all of which need to be kept clean in order to maintain a high manufacturing quality. Generally, the cleaning procedures involved therein may decrease substrate throughput. Therefore, there is a need in the art for an efficient cleaning method and apparatus for processing flexible substrates, such as OLED structures, semiconductor structures and other modern more sophisticated devices to ensure substrate throughput is maximized.